selftests/bpf: Add unit tests for pointers in global functions

test_global_func9  - check valid pointer's scenarios
test_global_func10 - check that a smaller type cannot be passed as a
                     larger one
test_global_func11 - check that CTX pointer cannot be passed
test_global_func12 - check access to a null pointer
test_global_func13 - check access to an arbitrary pointer value
test_global_func14 - check that an opaque pointer cannot be passed
test_global_func15 - check that a variable has an unknown value after
		     it was passed to a global function by pointer
test_global_func16 - check access to uninitialized stack memory

test_global_func_args - check read and write operations through a pointer

Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210212205642.620788-5-me@ubique.spb.ru

1 files changed, 132 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/test_global_func9.c b/tools/testing/selftests/bpf/progs/test_global_func9.c
new file mode 100644
index 000000000000..bd233ddede98
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_global_func9.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <stddef.h>
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+struct S {
+	int x;
+};
+
+struct C {
+	int x;
+	int y;
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 1);
+	__type(key, __u32);
+	__type(value, struct S);
+} map SEC(".maps");
+
+enum E {
+	E_ITEM
+};
+
+static int global_data_x = 100;
+static int volatile global_data_y = 500;
+
+__noinline int foo(const struct S *s)
+{
+	if (s)
+		return bpf_get_prandom_u32() < s->x;
+
+	return 0;
+}
+
+__noinline int bar(int *x)
+{
+	if (x)
+		*x &= bpf_get_prandom_u32();
+
+	return 0;
+}
+__noinline int baz(volatile int *x)
+{
+	if (x)
+		*x &= bpf_get_prandom_u32();
+
+	return 0;
+}
+
+__noinline int qux(enum E *e)
+{
+	if (e)
+		return *e;
+
+	return 0;
+}
+
+__noinline int quux(int (*arr)[10])
+{
+	if (arr)
+		return (*arr)[9];
+
+	return 0;
+}
+
+__noinline int quuz(int **p)
+{
+	if (p)
+		*p = NULL;
+
+	return 0;
+}
+
+SEC("cgroup_skb/ingress")
+int test_cls(struct __sk_buff *skb)
+{
+	int result = 0;
+
+	{
+		const struct S s = {.x = skb->len };
+
+		result |= foo(&s);
+	}
+
+	{
+		const __u32 key = 1;
+		const struct S *s = bpf_map_lookup_elem(&map, &key);
+
+		result |= foo(s);
+	}
+
+	{
+		const struct C c = {.x = skb->len, .y = skb->family };
+
+		result |= foo((const struct S *)&c);
+	}
+
+	{
+		result |= foo(NULL);
+	}
+
+	{
+		bar(&result);
+		bar(&global_data_x);
+	}
+
+	{
+		result |= baz(&global_data_y);
+	}
+
+	{
+		enum E e = E_ITEM;
+
+		result |= qux(&e);
+	}
+
+	{
+		int array[10] = {0};
+
+		result |= quux(&array);
+	}
+
+	{
+		int *p;
+
+		result |= quuz(&p);
+	}
+
+	return result ? 1 : 0;
+}